Dynamics of Blood Pressure Elevation and Endothelial Dysfunction in SHR Rats During the Development of Arterial Hypertension.

The dynamics of systolic and diastolic BP and vasodilatory activity of the endothelium in SHR and Wistar-Kyoto rats was studied from the 5th to the 12th week of life. Systolic and diastolic BP did not differ in 5-week-old SHR and Wistar-Kyoto rats. After the 6th week of life, two stages of arterial hypertension development were observed in SHR. Stage 1 (weeks 6-8) was characterized by a significant increase in systolic and diastolic BP that exceeded the corresponding parameters in Wistar-Kyoto rats by 26-32%. Vasodilatory activity of the endothelium was similar in rats of both strains at the age of 5-7 weeks. Stage 2 (weeks 9-12) in SHR rats was characterized by further increase in systolic and diastolic BP that exceeded the corresponding parameters in Wistar-Kyoto rats by 54-89%. The increase in BP during this period was accompanied by a significant decrease in endothelium-dependent relaxation (by 14-16% compared to that in Wistar-Kyoto rats of the same age).